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Author Topic: Milwaukee Midget  (Read 1648341 times)
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« Reply #7170 on: May 29, 2018, 11:34:38 PM »

Those slave cylinders are free floating 15/16" so just put a small C-clamp in it so you can bleed it off the trans & then bolt it up. If you pull the trans just unbolt it & put the clamp in or you can make a tool that'll go through the boot & hook around the bleeder to hold it together.
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« Reply #7171 on: May 30, 2018, 08:05:38 AM »

Those slave cylinders are free floating 15/16" so just put a small C-clamp in it so you can bleed it off the trans & then bolt it up. If you pull the trans just unbolt it & put the clamp in or you can make a tool that'll go through the boot & hook around the bleeder to hold it together.
  Sid.

One would think, and I have tried that in the past.  The issue then becomes accessing the upper ear that bolts to the bellhousing with the combination of hose, pushrod and clutch fork in place.

No, remote is the way to go - we're better than half way there.
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"Problems are almost always a sign of progress."  Harold Bettes
Well, I guess we're making a LOT of progress . . .  rolleyes

We are NOT rebuilding . . . We are reloading.

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« Reply #7172 on: May 31, 2018, 02:44:33 AM »

Looking very good gents.

Excuse my ignorance on bmc ---not the  a series,  but do you run a crank timing end damper ( harmonic balancer)  for your relatively short but fast runs?  and then a technical Question, would you dynamically balance the rotating bits ( see fordboys beaut photo on page 468) with it included ?  Cheers Darryl
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« Reply #7173 on: May 31, 2018, 07:38:08 PM »

Ignorance of BMC started with Lord Nuffield - trust me, you are not alone.  

We elected to skip the damper for the following reasons -

1. The original damper was intended for a 1400 with a longer stroke.  It was a rubber molded steel affair, and we had no reasonable expectation that it would last at 8,000 RPM, nor were we convinced it would do any good on this configuration.

2. When we were having the crank made, I checked into the idea of using an aftermarket Chevy liquid damper, and simply having the snout of the crank ground to accept the Chevy piece.  It proved unworkable due to the concentric oil pump drive having a smaller diameter than that of a SBC damper.

3. Note the short stroke of the engine - 55.5 mm - the rod journals OD does not extend beyond the OD of the main journals.  It's made of EN40, and the combination makes the crank quite stiff and exceptionally over-engineered for a 1 liter engine.  The radius grinding is impeccable, as is the rest of the workmanship on the crank.

4. There are plenty of 1275 A-series racing engines running without a damper, and we're talking a much longer stroke with only 3 main bearings!  Personally, I wouldn't do it, but the K-series bottom end is a lot more stable than the A-series, plus it utilizes a girdle.

5. I may be wrong on this, and I certainly wouldn't count on it if not for the other factors involved, but I mentioned the oil pump earlier - it's located on the front of the engine and is a concentric drive arrangement that encircles the crankshaft.  It's my thought that the pump acting against the oil absorbs some of the harmonics, and I suspect the same holds true for the cam belt.  Might be insufficient exertion against the harmonics the crank is likely to see, or I might be completely wrong, but if I am, Ive still got responses 1-4.

The crank came balanced from the grinder, so I wasn't surprised when Mark posted up that bit of news.  

We'll likely just match weight the rod/piston combinations and see if we can keep it to within a gram per assembly.  That worked on the Grenade.
« Last Edit: May 31, 2018, 08:54:39 PM by Milwaukee Midget » Logged

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« Reply #7174 on: June 01, 2018, 02:42:20 AM »

Re Balancer/ Damper

Thanks Chris for the info.  I agree a  5 mains is in a much better position to handle vibrations than a 3 mains and given the rpm you will be turning it is no guarantee that anything ' normal' would be effective. Again though ( using other peoples time , money and expertise of course) it would be good to know with evidence what the lightened flywheel etc does to move any harmonics Cheers Darryl
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« Reply #7175 on: June 01, 2018, 12:34:39 PM »

Chris,
I am sure that Mark will agree that your motor will have an harmonic at some rpm, hopefully below your max hp rpm and the idea of course is to drive through that rpm and not spend any time there as that is the time that parts start to fail. That rpm that the harmonic occurs is based upon the  crank/rods/pistons/flywheel/clutch assembly polar moment of inertia and the torsional stiffness of the crank. It can be calculated and I have seen the math but it is somewhat complicated. You can change it by changing the rotating mass, the flywheel is the easiest to change. A heavy flywheel will lower the frequency a lighter   wheel will raise it. The quest, as I see it for a land racing motor, is to get the frequency below the rpm that the engine is at when you shift into top gear as that is the gear that you will be in the longest.

Midget racers, not MG Midgets!, do not run dampeners and they typically have an harmonic in the 6-7000 rpm range but they turn them to 9000+ and drive through the harmonic range. Every inline 4 cylinder has the unique trait of having all of the piston/rods come to a complete stop every revolution of the crank. This induces a very high instantaneous torque, as much as 8 times the average torque that is seen on a dyno. This torque can disrupt cam and ignition timing to the point that the engine will not make the expected power. Your motor uses a "rope" drive for the cam and this can dampen much of this torque surge to the cams. When the Cosworth DFV was first ran on the dyno they were failing the cam drive gears, so they measure the instantaneous torque and found it was multiple times higher than the calculated drive torque. They added a spring hub to one of the cam drive gears an this attenuated the torque spikes to the level that the gears would live. All engines are harmonic limited in some way, intake and exhaust gases have governing frequency's, the rotating masses have one, as do the valve actuation systems and control of these frequencies is one of the keys to having a high performance engine.

Rex
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« Reply #7176 on: June 01, 2018, 01:32:20 PM »

This torque can disrupt cam and ignition timing to the point that the engine will not make the expected power. Your motor uses a "rope" drive for the cam and this can dampen much of this torque surge to the cams.

One of the upgrades we made to the "A" was to upgrade to a belt drive cam arrangement - a Vizard recommendation.  Anything we could do to minimize spikes through the valvetrain in a design that was, at best, kinda iffy right out of the box.

It gets even more complicated and quirky when you drive a distributor off of the cam.  You get monkey-motion in the drive sprocket, chain, cam sprocket and the distributor drive, along with the forces exerted on the lobes by the lifters, so yes, Rex, with all of those stacked tolerances, I wouldn't be a bit surprised if power was not where it was targeted.

I fitted a GM style knock sensor to the Grenade, but despite the belt drive and crank trigger, the crank assembly and valve train was so noisy that one couldn't isolate genuine knock in the ignition controller, so we just left it off.

All kinds of noises we don't hear.  The problem is, once they become audible, it's usually too late!  shocked 


 
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"Problems are almost always a sign of progress."  Harold Bettes
Well, I guess we're making a LOT of progress . . .  rolleyes

We are NOT rebuilding . . . We are reloading.

GOD SAVE MG - The Queen can take care of herself!
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« Reply #7177 on: June 01, 2018, 09:46:20 PM »

I used a Electromotive ignition on the Bantam .  The flywheel was notched 60 minus 2 and the sensor mounted through the crankcase ,,  absolutely no play in timing ..  It is deadfire with the basic control box , ignition setting in 3 stages of rpm and rev limiter .  No computer  type inputs .  STEVE


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« Reply #7178 on: June 02, 2018, 10:15:18 AM »

Midget and Fordboy: there is a thread on Speedtalk about torqueing aluminum heads and torque plates about which Hoffman900 posted an article from Raceengineering about the Rover K and its long bolts etc. You both are likely familiar with the issue but thought you might be interested in the comments.

http://speedtalk.com/forum/viewtopic.php?f=1&t=53476
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« Reply #7179 on: June 03, 2018, 05:50:49 AM »

Weekend Update, uno . . . . . .

From the Wednesday morning Vulcan Mind Meld of 5/16/2018, (NO, I don't know what stardate that is . . . .) the mental gymnastics of one "wiggle pin" . . . . . .

Output from the brain of a terran  . . . . . . . .  NOT a Krell . . . . . . . .



And I still can't get the terran to change his default dimensioning specs from a limit of 2 decimal places.   Approved for production, nonetheless.

Things are happenin' below the dreaded . . . . . "cheddar curtain" . . . .

Und later: crankenshaften spinnin'   ja.

 cheers  cheers  cheers
Dimensioningco-ordinatorboy

OK then . . . . . .

Belated Further Update . . . . from 5/30/2018

Using the mind melding capability of the Vulcans, the mental ability of the Krell to create at will, and subconsiously, morphed with the laser sintering processing of the Terrans (the most backward of the races . . . ) and, and, and, . . . . .

Oh hell, Mikey just chewed it out from a chunk of 6061 plate on his manual vertical mill, equipped with digital positioning . . . . .  (But it would have been way cool laser printed out of say, Titanium!)

Front face:


Rear face:



No more chintzy plastic for residents of Sconnie Nation! !

Yeah, yeah, I know for a fact they still drink their fermentables from, gasp, plastic cups . . . . .        the heathens, it's not like they don't have sand to make glass . . . . .

Might have to do a bit of corner rounding, or perhaps localized trimming or reliefs, but other than that, pretty much ready for the "co-mingling of the species" . . . . . . .


But, otherwise, things continue to happen below the "Cheddar Curtain" whilst you develop your character on "Non-Celebrity Apprentice of Beerhaven" in preparation for live streaming on Hulu . . . . . .

Maybe more later . . . .

 cheers
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« Last Edit: June 03, 2018, 06:02:09 AM by fordboy628 » Logged

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« Reply #7180 on: June 03, 2018, 06:56:32 AM »

Sweet!! cheers
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Jack Iliff
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« Reply #7181 on: June 03, 2018, 09:17:45 AM »

Been a bit busy here, too.

Finished the driveshaft tunnel yesterday - secured and sealed.

I'll be getting the header built this Tuesday or Wednesday, which means I need to fetch the trailer tomorrow PM in order to drag the whole pile out to Watertown.

On the agenda is getting the driveshaft shortened - also this week.

Mark, let me know which type of Hylomar you're looking for - I'll drop by Pegasus and pick it up.

I've got temp, oil and fuel pressure senders on their way - should arrive Monday.

Rather than run redundant senders, I'm looking to install one of these - pulls all of the information out of the ECU -

https://www.youtube.com/watch?time_continue=154&v=DdIEZTQEkwE

That will save me a few days of rehabbing the dash and additional oil line plumbing, plus simplifiy the rest of the electronics.


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"Problems are almost always a sign of progress."  Harold Bettes
Well, I guess we're making a LOT of progress . . .  rolleyes

We are NOT rebuilding . . . We are reloading.

GOD SAVE MG - The Queen can take care of herself!
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« Reply #7182 on: June 03, 2018, 03:30:17 PM »


Been a bit busy here, too.

I've got temp, oil and fuel pressure senders on their way - should arrive Monday.

Rather than run redundant senders, I'm looking to install one of these - pulls all of the information out of the ECU -

https://www.youtube.com/watch?time_continue=154&v=DdIEZTQEkwE

That will save me a few days of rehabbing the dash and additional oil line plumbing, plus simplifiy the rest of the electronics.



midget,

Just so I have this straight, the time line arc of this project is:

1/   1935 or so, for the original engine design?
2/   1962 or so, for the original body styling?
3/   1972 for the car body being used?
4/   1980-ish for the original race engine tech?
5/   powerplant transplant, designed circa 1988?
6/   2000+ ish technology for the current race engine?
7/   2008 or so for the ECU, controlling both ESC & EFI?
8/   2015 ECU & gauge monitoring capability?

DA**, I have had an effect on you!   grin

SO, then I postulate that:    hawkeye persistence + illini love of technology, magic    might = reasonable chance of success? ? ? ?

 Dead Horse  cheers  Dead Horse
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« Reply #7183 on: June 03, 2018, 03:40:10 PM »


Been a bit busy here, too.

Mark, let me know which type of Hylomar you're looking for - I'll drop by Pegasus and pick it up.


midget,

Hylomar sealant, medium consistency, in the tube.   One tube ought to get it done.    Should be the same stuff Rover calls for to rebuild the engines, or at least similar enough.

This needs to be used where Rover has eliminated gaskets, ie, the bearing ladder, the oil sump, etc.

https://www.pegasusautoracing.com/productdetails.asp?RecID=972

 cheers
SurvivedHawkeyenationboy
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"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."     Albert Einstein
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« Reply #7184 on: June 03, 2018, 03:54:27 PM »

"Just so I have this straight, the time line arc of this project is . . . 1935 or so, for the original engine design?"

I've got an idea!

Instead of runnin' against modern engines, petition the SCTA for a Vintage Engine class for GTs.  No need to prepare for August it'll take years to get that rule change made.

In the mean time, you could opt for the ECTA and run in their Vintage-Engined 500cc Sports Car Class which I believe has an open record.  If not, try the 250cc class (tell them you'll disconnect 3 spark plug wires.  Don't worry, they won't check.).

Stan
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